ES2785662T3 - Covering system for silage preparation - Google Patents

Abstract

Covering system (1) for the preparation of silage, comprising at least one lower film (2) for narrowing against the surface of an animal feed (6), in which the lower film (2) has at least one layer oxygen barrier (3), which is composed of at least 50% by weight of materials from the group comprising polyamide, copolyamide, polyester, copolyester, polyethylene-vinyl alcohol, polyvinyl alcohol and / or mixtures of them, characterized in that the The lower film (2) has at least one inner protective layer (4) directed at the silage for the protection of the oxygen barrier layer (3) against substances in the silage, in which the lower film (2) has a thickness of maximum 60 μm and the oxygen barrier layer (3) is thicker than the protective layer (4) by at least a factor of 1.2.

Description

DESCRIPTION

Covering system for silage preparation

The invention relates to a covering system for the preparation of silage, comprising at least one lower film, which is tapering against the surface of the animal feed.

Silage is an animal feed preserved by lactic acid fermentation for useful animals, especially ruminants. But other renewable raw materials, which serve as an energy source in biogas facilities, can also be conserved by silage. In principle, all basic animal feeds can be ensiled, including grass (grass silage), corn (corn silage), clover or also cereals (such as whole plant silage).

Three basic forms are differentiated for the generation and storage of silage: the currently difficult to find tall silo, the flat silo (free-fermentation piles or corridor silos) and the bale or sleeve silo.

The most significant and most economical type of silage preparation by virtue of the quantity consists of covering with films the forage that is piled up on the ground in piles. Here it differs again according to corridor silos, which are limited towards the ground and on the side walls by concrete walls, and free-fermenting piles, which do not have side limiting construction walls. Such flat silos, i.e. free-fermentation piles or runner silos, are also referred to as pile silos. In a conventional way, stable polyethylene-based films have been used to cover the pile silos. However, when using these conventional films a mold formation always occurs again, due to the penetration of oxygen.

Document EP 1035762 B1 describes a plastic film, which consists of an insulated plastic material, airtight and in particular oxygen. The film comprises at least one layer of a polyamide.

Document EP 2286658 B1 describes a silage film, which has at least one layer of a resin composition, which has a saponified copolymer based on ethylene-vinyl acetate with a content of 20-60 mol% and a saponified copolymer a ethylene-vinyl acetate base with an ethylene content of 70 to 98%. According to the most recent state of the art, several films are used to cover the pile silos. In this respect, for silage in practice two films of different thicknesses are arranged one on top of the other. The bottom film, which is placed directly on the animal feed, is referred to as the bottom film. The thin bottom film is "sucked" almost to the freshly ensiled feed, so this film is also referred to as "suction film", "sealing film" or sealing film. The more closely the film adapts to the feed plant, the less oxygen remains after covering in the silo or the less oxygen can penetrate the feed plant during intake. By using an under film, which tapers against the animal feed, mold formation and unwanted yeast growth are prevented.

Covering systems are known, in which a thicker silage film is placed on this lower film. The thicknesses of the bottom films commonly used are in this respect about 40 pm, whereas the silage films commonly used have thicknesses in the range of 120-200 pm. The purpose of silage films is to protect the bottom film against ultraviolet light and mechanical stress.

In those usual systems with several films, the lower film is generally composed of a polyolefin film. The silage film is also usually a polyolefin film, however, it has a greater thickness than the lower film.

Document DE 1020090252948 B4 describes a covering system with a lower film of a polyamide and a silage film of a polyethylene. The thin bottom film of the polyamide tapers against the surface of the feed pile and therefore acts as an effective oxygen barrier, effectively preventing mold growth.

In EP 3 009 263 A1 a stretch film for wrapping material is described. The stretch film comprises a blocking layer, which is arranged between two layers of polyolefin. The film has a low permeability for oxygen and water vapor.

Lactic acid that originates in fermentation can attack the bottom film.

This can lead to deterioration of the polymer and consequently to a reduced service life or leaks.

The object of the invention is to provide a covering system for the preparation of silage, which effectively prevents the formation of mold, as well as the growth of yeast. For this, the cover system must stand out for its good mechanical durability and must offer security against damage by birds, hail and Similar. In addition, the cover system should stand out in the course of sustainable development for good recycling capacity and high resource efficiency.

This object is achieved according to the invention because the lower film has an inner protective layer, directed towards the silage, which protects the oxygen barrier layer against the action of substances that originate during silage, in particular the action of acid. lactic. The object is achieved according to the invention with a cover system as defined in claim 1. Other embodiments are set out in the dependent claims. A process according to the invention for the preparation of silage is defined in claim 20 and in claim 21 the use of the cover system is defined.

Preferably, the protective layer of the lower film is composed of at least 50% of materials from the group comprising polyethylene, polypropylene, ethylene-vinyl acetate (EVA) or ethylene-butyl acrylate (EBA), ethylene copolymers and other monomers of vinyl, as well as copolymers of propylene and other vinyl monomers.

By cleverly combining an oxygen barrier layer, which is preferably composed of polyamide, with a protective layer, which is preferably composed of polyethylene, a sufficiently flexible but stable bottom film is created, which is sucked up against the surface of the the pile of animal feed and consequently prevents the formation of cavities, simultaneously acts as a barrier to oxygen and additionally has a high resistance to lactic acid.

The thickness of the lower film is at most 60 pm, preferably at most 50 pm, in particular at most 40 pm. The thin embodiment of the bottom film, which comprises according to the invention an extremely effective oxygen barrier layer, which is combined with a protective layer, guarantees an effective suction of the bottom film and simultaneously an efficient oxygen barrier, which is protected against the action of lactic acid.

Furthermore, in order to prevent damage to the lower film, for example due to mechanical influences, it has been found to be particularly favorable for the lower film to have a thickness of at least 10 pm, preferably at least 15 pm, in particular at least 20 pm.

The oxygen barrier layer is thicker than the protective layer by at least a factor 1.2, preferably at least a factor 1.4, in particular at least a factor 1.6, where it is particularly favorable that the oxygen barrier layer is thicker than the protective layer by at least a factor 1.8. By means of this favorable ratio of the thicknesses of the oxygen barrier layer to the thickness of the protective layer, a lower film is created, which is flexible enough to approach the silage, simultaneously has a high impermeability against oxygen and is additionally protected effectively against the influences of lactic acid in the silage. In a variant of the invention, the ratio of the thickness of the oxygen barrier layer to the thickness of the protective layer is 2: 1. Thus, for example, a bottom film having a polyamide oxygen barrier layer having a thickness of 20 µm and a polyethylene protective layer of 10 µm has proven to be advantageous.

The oxygen permeability of the multilayer bottom film is according to DIN 53380-3 at 23 ° C and 50% humidity snn cm3 300 cmi ,

relative maximum ^{m 2-d-bar} ' preferably maximum ^{m 2-d-bar'} in particular as

^{. .} _maximum 200 _m ^; _-D-bar ^.

Within the framework of the present invention, this water permeability is determined according to DIN 53380-3 at 23 ° C and 50% relative humidity. In a particularly advantageous variant, the lower film exhibits permeability to

oxygen max

Preferably, the combination according to the invention of the oxygen barrier layer with the protective layer in the lower film is selected so cleverly that, together with an oxygen permeability that is as low as possible, a water vapor permeability is simultaneously selected as high as possible. The water vapor permeability of the lower film is according to ISO 15106-3 at 23 ° C and 85% relative humidity of the air at least 5 9 jo

re at least _ - _ 15 9 ,

^{m 2 d '} preferably ^{m 2-d'} in particular at least ^{m 2-d.} In this way it is achieved that the moisture of the food plant can diffuse through the lower film and consequently a moisture balance is set between the food plant and the lower film. Thanks to this diffusion of moisture through the lower film, a thin moisture film can be formed between the lower film and a silage film, which contributes to a separation of the lower film from the silage film. On the contrary, in conventional bottom films a diffusion of moisture through the bottom film is largely excluded, so that the moisture from the film accumulates towards the bottom film and cannot pass through the bottom film. On the contrary, in the film according to the invention, a part of the moisture passes through the lower film and accumulates as a film between the lower film and the silage film, so that for this reason a separation of both films is caused and therefore I know You can suck the bottom film against the surface of the animal feed plant.

In a particularly advantageous embodiment of the invention, the covering system comprises, together with the lower film according to the invention, a silage film. The silage film is preferably significantly thicker than the lower film and has the aim of protecting the lower film against mechanical stress and possibly also ultraviolet light.

In a variant of the invention, the lower film according to the invention and the silage film form a unit for covering the pile of animal feed in one working stage. This unit is preferably formed in that the bottom film and the silage film are wound or folded together, so that unwinding or unfolding is possible in one working step. Thanks to this combination of a silage film with a lower film, an effective oxygen barrier is created, which can be applied to the silo in just one working step. The bottom film adherent to the silage film is detached autonomously from the silage film after use in a relatively short time and is sucked up against the silage, so that the silage is effectively sealed against oxygen penetration. Therefore, the bottom film is also referred to as the sealing film. After laying with incipient fermentation process, the lower film absorbs the moisture from the silage product. In this regard, its moisture, resistance to penetration and elongation are raised. The permeability to water vapor according to the invention of the lower film forces the separation of the lower film from the silage film. The water vapor from the silage diffuses through the lower film and condenses on the silage film, which blocks the water vapor. After a few days the separation of the film combination is perfect. The bottom film tapers against the surface of the silage. Thus, nests of moisture and the associated risk of mold can be effectively avoided.

The unit according to the invention from the lower film with a silage film is combined in this respect so that, after spreading of this unit in a working step, the lower film separates from the silage film and then narrows against the surface of the pile.

In this variant of the invention, within the lower film the protective layer is present separately from the oxygen barrier layer. In this regard, the bottom film can already be made up of two separate layers from the beginning or the separation of the protective layer from the oxygen barrier layer takes place only after the spreading of the covering system. The protective layer is detached autonomously from the oxygen barrier layer in this case then only after spreading of the covering system. In this variant of the invention, the protective layer is sucked up against the silage. Thanks to the oxygen barrier layer, the silage is effectively sealed against the penetration of oxygen.

Preferably, the silage film of the cover system has a lower permeability to water vapor than the lower film. In this respect, it turns out to be favorable that the water vapor permeability of the silage film _{is according to the ISO 15106-3 standard at 23 ° C and 85% relative humidity at most} 3-0

^{2 5 2 Q} ^

preferably ' ^{m 2-d'} - in --- p - a - rt'icu mla2r w. 'From m2 is dte. In this way, the water vapor, which diffuses from the silage through the lower film, can accumulate in the silage film, blocking the water vapor according to the invention. In this way the separation of the bottom film from the silage film is improved, so that the silage film can be perfectly sucked against the feed plant and thus forms an adherent sealing film.

Preferably, the lower film has in the oxygen barrier layer, together with materials from the group comprising polyamide, copolyamide, polyester, copolyester, polyethylene-vinyl alcohol, polyvinyl alcohol and / or mixtures of them at most 20% by weight of polymeric compounds, preferably no other polymeric compound.

In a particularly advantageous variant, the oxygen barrier layer of the lower film consists of polyamides and copolymers, preferably mixtures of PA 6, PA 6/66, PA66, PA 6I6T and / or other aliphatic, aromatic or partially aromatic polyamides or copolyamides . Preferably, the oxygen barrier layer contains at least 50%, preferably at least 70% and still more preferably at least 90% of one or more materials from the group comprising polyamide and copolyamide, preferably PA6, PA66, PA 6 / 66, PA 6I6T and / or other aliphatic, aromatic or partially aromatic polyamides or copolyamides.

The lower film is composed according to the invention at least of an oxygen barrier layer and a protective layer. The bottom film can have additives in one, several or all of the layers, for example, to increase the stability against ultraviolet radiation and / or lubricants and / or mineral antiblocking additives to reduce the friction coefficients of the film surface. and / or additives for coloring.

It has turned out to be advantageous to lay the covering system with a greater fraction of water in the film lower than that which is contained after extrusion of the film. Preferably, a moisture content is 2% by weight or more, based on the materials contained in the lower film of the group comprising polyamide, copolyamide, polyester, copolyester, EVOH and PVOH. The water content can be introduced, for example, via aerosols or a water bath. water during production.

The silage film preferably contains low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene α-olefin copolymers (LLDPE), ethylene vinyl acetate copolymers (EVA). ), copolymers of ethylene and unsaturated ethylenic acids or esters, in particular acrylic acid, methacrylic acid and its esters (ethyl methacrylate EMA), ethylene-ethyl acrylate (EEA), ethylene-butyl acrylate (EBA), polypropylene (PP ), heterophasic (block co-PP) or homogeneous (random co-PP) copolymers, polyethylene and ethylene copolymers. It is advantageous that no other polymeric components are contained outside of the materials from the group comprising polyethylene, polypropylene, copolymers of ethylene and other vinyl monomers, as well as copolymers of propylene and other vinyl monomers. Vinyl monomers are understood to be those with an ethylene group, which can be copolymerized with ethylene. These include primarily, but not exclusively, C2-12 olefins - for example ethylene, propylene, butene, pentene, hexene, octene-, acrylic acid and its esters, methacrylic acid and its esters, styrene, diene - for example butadiene, isoprene-, vinyl acetate, cycloolefins - for example norbonne, cyclopentadiene- and carbon monoxide.

The silage film may contain mineral fillers, such as, for example, but not exclusively, calcium carbonate or talc to increase rigidity. The silage film may contain additives in customary amounts, for example UV stabilizers and / or lubricants and / or mineral antiblocking additives for reducing the friction coefficients of the film surface and / or additives for coloring the film.

The silage film preferably has a thickness between 50 µm and 200 µm, especially preferably between 50 µm and 150 µm, and particularly preferably between 60 and 120 µm.

It has turned out to be particularly favorable that in the cover system according to the invention the bottom film and the silage film are manufactured together by coextrusion. In this respect, it turns out to be especially advantageous if the bottom film and the silage film are produced during coextrusion with a low adhesion of compounds, for the separation of the bottom film from the silage film. By coextrusion with low compound adhesion, a covering system is created, in which the bottom film can be separated from the silage film after spreading in one working step. The covering system is in this respect a pre-assembled unit, where in this pre-assembled unit the lower film with the silage film is wound and / or folded together and thus can be applied in a working step by unwinding and / or unfolding. common over the pile silo.

In a preferred embodiment, at least one layer of the covering system is composed of a monolayer or multilayer extruded plastic film with at least one layer containing a foam structure. This is especially favorable for the separation of the bottom film from the silage film in the cover system manufactured by coextrusion with little adhesion of compounds.

The unrolled cover system preferably has a rectangular shape.

The width of the covering system is preferably at least 3 m, particularly preferably at least 4 m, in particular at least 5 m and / or at most 21 m, especially preferably at most 20 m, in particular at most 19 m .

The length of the covering system is preferably at least 20 m, particularly preferably at least 30 m, in particular at least 40 m.

The invention is explained below by way of examples, however, without being limited to the especially described embodiments. Unless otherwise stated, percentage data refers to weight, if in doubt to the total weight of the mixture. The invention also relates to all combinations of convenient, favorable and preferred configurations, as long as they are not mutually exclusive. The indications "approximately" or "close to" in connection with a numerical indication mean that values greater or less in 10% or greater or less values in 5% and in any case the greater or less values in 1 %.

In this regard, the following figures show:

Figure 1, a schematic sectional representation through the covering system according to the invention, Figure 2, the covering system directly after application on the food plant,

Figure 3, the detachment of the lower film from the silage film.

Figure 1 shows a cover system 1 for the preparation of silage. The covering system 1 comprises a lower film 2. The lower film has an oxygen barrier layer 3 and a protective layer 4.

In the exemplary embodiment, the thickness of the lower film 2 is approx. 30 pm, where the oxygen barrier layer 3 has a thickness of 20 pm and the protective layer 4 a thickness of 10 pm. The oxygen barrier layer 3 is therefore thicker than the protective layer 4 by factor 2.

The thin bottom film 2 is sucked by adhesion on the freshly ensiled feed. Thanks to this narrowing, the formation of cavities is prevented.

In addition to the separation of the lower film 2 from the silage film 5, a separation of the oxygen barrier layer 3 and the protection layer 4 can also occur within the lower film 2. This variant is not represented in the figures.

In the example, the oxygen barrier layer 3 consists of at least 80% PA 6/66.

According to the invention, in the lower film 2 the oxygen barrier layer 3 is combined with a protective layer 4. The protective layer 4 is composed of at least 50%, preferably at least 70%, in particular at least 90% % of the materials in the group comprising polyethylene, polypropylene, ethylene-vinyl acetate (EVA) or ethylene-butyl acrylate (EBA), copolymers of ethylene and other vinyl monomers, as well as copolymers of propylene and other vinyl monomers. This pololefinic protective layer 4 protects the oxygen barrier layer 3 against the action of lactic acid, which originates during the fermentation of the silage. In this way a lower film 2 is created, which due to its small thickness of only 30 pm is sucked against the surface of the animal feed and narrows so that the surface of the medium is sealed against oxygen penetration and simultaneously prevented effectively the formation of liquid esters, so that no mold formation occurs. Simultaneously, by thinly coating the oxygen barrier layer 3, which preferably consists of a polyamide, with a protective layer 4, which is preferably composed of a polyolefin, a high durability and long service life of the lower film 2 is guaranteed Thus, throughout the entire fermentation process an oxygen-tight silage cover is obtained.

In the exemplary embodiment according to the representation in FIG. 1, the oxygen barrier layer 4 consists of a polyethylene.

The covering system 1 according to the invention represented in figure 1 comprises, together with the lower film 2, a silage film 5. For the manufacture of the covering system 1, the silage film 5 has been manufactured by coextrusion with the lower film 2. According to the invention , the bottom film 2 and silage film 5 form a combined unit for covering the pile of animal feed in one working stage.

The silage film 5 has a thickness of 80 pm in the exemplary embodiment. Together with the lower film 2, the thickness of the cover system 1 is therefore approx. 110 pm.

The silage film 5 is composed of at least 70% polyethylene.

Figure 2 shows the cover system 1 directly after a pile of animal feed 6 has been applied. The bottom film 2 adheres to the silage film 5.

Figure 3 then shows a situation in which the lower film 2 has detached from the silage film 5 and has narrowed against the surface of the pile of animal feed 6.

Claims (21)

1. Covering system (1) for preparing silage, comprising at least one lower film (2) for narrowing against the surface of an animal feed (6), in which the lower film (2) has at least an oxygen barrier layer (3), which is composed of at least 50% by weight of materials from the group comprising polyamide, copolyamide, polyester, copolyester, polyethylene-vinyl alcohol, polyvinyl alcohol and / or mixtures of them, characterized because the lower film (2) has at least one inner protective layer (4) directed to the silage for the protection of the oxygen barrier layer (3) against substances in the silage, in which the lower film (2) has a thickness of maximum 60 pm and the oxygen barrier layer (3) is thicker than the protective layer (4) by at least the factor 1.2. Cover system according to claim 1, characterized in that the protective layer (4) consists of at least 50% by weight, preferably at least 70% by weight, in particular at least 90% by weight, of materials from the group comprising polyethylene, polypropylene, copolymers of ethylene with other vinyl monomers, as well as copolymers of propylene and other vinyl monomers, ethylene-vinyl acetate (EVA) or ethylene-butyl acrylate (EBA). Cover system according to claim 1 or 2, characterized in that the lower film (2) has a thickness of at most 50 pm, in particular at most 40 pm and / or at least 10 pm, preferably at least 15 pm, in particular at least 20 pm. Cover system according to any one of claims 1 to 3, characterized in that the oxygen barrier layer (3) is thicker than the protective layer (4) by at least a factor 1.4, in particular at least by a factor 1.6. 5. Covering system according to any of claims 1 to 4, characterized in that the lower film (2) has an oxygen permeability according to DIN 53380-3 at 23 ° C and 50% relative humidity of a maximum of 500 _ i " , / j 300 _ 200 preferably maximum '* in particular

6. Covering system according to any of claims 1 to 5, characterized in that the lower film (2) has a permeability to water vapor according to ISO 15106-3 at 23 ° C and 85% relative humidity of at least 5 j ¡_ , 10 _u_. ^^ ~ t ~ «3.r> preferably at least« ** • «’ in particular at least ■ '-7. Covering system according to any of claims 1 to 6, characterized in that the lower film (2) of at least one layer (3) together with materials from the group comprising polyamide, copolyamide, polyester, copolyester, polyethylene-vinyl alcohol, polyvinyl alcohol and mixtures thereof contain at most 20% by weight of other polymeric compounds, preferably at most 10% by weight, in particular no other polymeric components. Covering system according to any one of claims 1 to 7, characterized in that the oxygen barrier layer (3) of the lower film (2) is made up of polyamide and / or copolyamide. Covering system according to any one of claims 1 to 8, characterized in that the lower film (2) contains in at least one layer (3, 4) additives to increase stability with respect to ultraviolet radiation and / or lubricants and / or Mineral antiblocking additives to reduce the friction coefficients of the film surface and / or additives for coloring the film. 10. Covering system according to any of claims 1 to 9, characterized in that the covering system (1) has a silage film (5), which with the lower film (2) forms a unit for coating in a working stage, wherein the unit is preferably formed in that the lower film (2) and the silage film (5) are wound and / or folded together for common unwinding and / or unfolding in a working step. Covering system according to claim 10, characterized in that the lower film (2) can be separated from the silage film (5) to constrict against the surface of the pile of animal feed (6). Covering system according to claim 10 or 11, characterized in that the silage film (5) has a lower permeability to water vapor than the lower film (2). 13. Covering system according to any of claims 10 to 12, characterized in that the silage film (5) 3 t, has a water vapor permeability according to ISO 15106-3 of maximum -s-3 ¹ 215 ^jj j 2 j O

preferred maximum ^{** • -} in particular maximum at 23 ° C and 85% relative humidity. 14. Covering system according to any of claims 10 to 13, characterized in that the silage film (5) is made up of at least 70% by weight of one or more materials from the group: - low-density polyethylene (LDPE), - medium density polyethylene (MDPE), - high-density polyethylene (HDPE), - copolymers of ethylene and a-olefin (LLDPE), - ethylene vinyl acetate copolymers (EVA), - copolymers of ethylene and acrylic acid, methacrylic acid or their esters, - ethylene-butyl acrylate (EBA), - polypropylene (PP), - heterophasic (block co-PP) or homogeneous (random CE-PP) copolymers of polyethylene and ethylene. 15. Covering system according to any of claims 10 to 14, characterized in that the lower film (2) and the silage film (5) are jointly manufactured by coextrusion with low adhesion of compounds to separate the lower film (2) from the film silage (5). 16. Covering system according to any one of claims 10 to 15, characterized in that at least one film, preferably the silage film (5), has a foam structure in at least one layer for separating the silage film (5) from the lower film (2). Covering system according to any one of claims 10 to 16, characterized in that the silage film (5) has a thickness of at least 50 pm, preferably at least 60 pm, in particular at least 70 pm and / or at most 120 pm , preferably at most 110 pm, in particular at most 100 pm. Covering system according to any one of claims 1 to 17, characterized in that the protective layer (4) is separated from the oxygen barrier layer (3). 19. Roll with a cover system according to any one of claims 1 to 18. 20. Procedure for preparing silage with the following stages: - application of a covering system (1) according to any of claims 1 to 18, in which a lower film (2) is applied together with a silage film (5) in a working step on a pile of animal feed (6), - wherein the bottom film (2) is released from the silage film (5) by moisture softening of the stack (6) and tapers against the surface of the animal feed stack (6). 21. Use of a covering system according to any of claims 1 to 18 for covering pile silos, such as corridor silos or free-fermentation piles in a working stage.